During the winter, we had some blankets stacked against the outside-facing wall of our master bedroom. Cleaning up recently, we found mildew on the wall and blankets. Why did this happen?

Lyndon

Keeping the blankets against the outside wall prevented air from circulating properly. The cold air outside and the warm air inside led to condensation that produced the mildew. In the future, leave some breathing room – about six inches – between the blankets and the wall and the problem will probably never happen again.